Safety device for power leaf brake



April 21, 1964 H. HADDEN AEETY DEVICE FOR POWER LEAF BRAKE Filed Aug.10. 1961 INVENT OR.

I'ENRY HADDEN ATIORNEYS United States Patent 3,129,745 SAFETY DEVICE FORPQWER LEAF BRAKE Henry Hadden, Bedford, Ohio, assignor to The StandardOil Company, Cleveland, Ohio, a corporation of Ohio Filed Aug. 10, 1961,Ser. No. 130,557 1 Claim. (Cl. 15339) This invention relates to a powerleaf brake and, more particularly, to a safety device for a power leafbrake.

Power leaf brakes are a type of press brake commonly used in industryfor the cold bending of metal sheets, bars, plates and the like. Thetype of power leaf brake here concerned comprises a table to which workmay be clamped having a normally raised workpiece engaging member with anormally vertical leaf member depending rearwardly therefrom. When thebrake is operated, the table rotates forwardly to effect a bend and thenreturns to its original position. During this operation the rearwardleaf is, of course, also rotated. Since the operator is usually standingclose to the machine to position the material before clamping it inplace for bending, there is a constant danger that the rearward leafwill pinch the operators foot in its return to normal position.

It is therefore an object of this invention to provide a safety devicefor a power leaf brake. Another object is to provide such a device thatwill function as a safety foot guard for such a brake.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claim, the following description and theannexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of but afew of the various ways in which the principle of the invention may beemployed.

In said annexed drawings:

FIG. 1 is a perspective view of a power leaf brake in its normal or restposition;

FIG. 2 is a partial sectional view showing the safety guard and itsmounting taken along line 2-2 of FIG. 1;

FIGS. 3 and 4 are partial sectional views similar to FIG. 2 showing theleaf member and guard in progressively raised positions.

Referring now to the drawings in detail, the power leaf brake is shownhaving a rotatable table which comprises a normally raised workpieceengaging member or ram 11 and a normally vertical leaf member 12. Theworkpiece engaging member 11 has a projecting forming or bending die 13which when the table is rotated presses the workpiece in a die-pit (notshown). The leaf member 12 depends from the rear of member 11 and whenthe table is rotated the leaf member 12 swings out from a nearlyvertical position to a more horizontal position as shown in FIGS. 2, 3and 4. The power leaf brake shown is mounted over a well or pit 14 inthe floor to receive the lower part of the leaf member 12. It is obviousthat during operation it would be relatively easy for an operator tohave his foot caught in the space 15 shown in FIG. 4 when the leafmember 12 descends again into the well 14. This is effectively preventedby the safety foot guard 16. The guard 16 is shown as a grill having aseries of horizontal bars 17 with supporting cross pieces 18 thereon.The guard has a pair of short inwardly directed pins 19 which fitloosely within a pair of horizontal sockets 20 which are welded orotherwise fastened to the leaf member 12. The bottom horizontal bar onthe guard 16 has a roller 21 thereon which may be of any suitabletubular material, including wood or plastic. The floor surrounding theleaf member 12 and well 14 is preferably covered with a rough surfacedsteel mat 22 to protect the floor and also to give the operator betterfoot traction.

When the leaf member 12 is at rest as shown in FIGS. 1 and 2, the guard16 effectively covers the space between the well 14 and the leaf member12 so as to prevent the operator from stepping therein; the same is truewhen the leaf member 12 is only slightly raised as shown in FIG. 3. Whenthe leaf member 12 is raised even higher as shown in FIG. 4, it isobvious that the operator may put his foot underneath the guard roller21 but is prevented from getting his foot underneath the leaf member 12.Since the guard 16 is hinged when it descends, his foot will not behurt.

The roller 21 serves the purpose of permitting the bot tom of the guardto ride smoothly over the mat 22. In addition, the action of the roller21 on the guard permits the operator to more quickly and easily withdrawhis foot therefrom since the freely rolling surface prevents anyprojections on the shoe from being caught by the guard.

The brake itself is a conventional one having electric push buttoncontrols 23 and being powered by hydraulic plungers 24. Since, however,details of construction of the brake, other than those described, formno part of this invention it will not be further discussed herein.

This invention has the advantage of rendering a potentially dangerousitem of machinery safer with a minimum of structural modifications andwithout detracting from the smooth operation and efficiency of themachine.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claim or the equivalent of suchbe employed.

I therefore, particularly point out and distinctly claim as myinvention:

In a power leaf brake disposed partially in a floor well and having aleaf member which moves to and from a substantially vertical conditionat one side of the brake in normal use of the same, with the bottom ofsaid leaf member swinging out of and into the well below the floor, asafety foot guard pivotally attached to said leaf member at areas spacedfrom the bottom of said leaf member for movement therewith and relativethereto, said guard comprising a horizontally elongated grill providedat its bottom with a horizontal bar member having a cylindrical rollermounted thereon, said roller providing smooth rolling movement of saidguard on said floor adjacent said well, said foot guard extendingpartially beyond the bottom of the leaf member when the latter iselevated above the floor to provide an effective extension thereof withthe guard engaging the floor adjacent the well at such side of the brakeas the leaf member swings from its raised to its lowered condition, thepivotal attachment of the guard providing for partial arrest of the sameas a result of such engagement with the floor and consequent movementrelative to the leaf member whereby said guard bridges the openingbetween said floor well and said leaf member in the lowered condition ofthe latter, said guard thereby preventing the insertion of objectsthrough said opening during said lowering movement of said leaf memberand the guard member to the lowered condition of the latter.

References Cited in the file of this patent UNITED STATES PATENTS1,998,245 Laukhuff Apr. 16, 1935 3,018,495 Hosbein Jan. 30, 1962 FOREIGNPATENTS 229,870 Great Britain Mar. 5, 1925 781,722 Great Britain Aug.21, 1957

